Question 141:

• JAMB 1980

A man stands one-third of the way between two walls and claps his hands, He hears two distinct echoes 1s apart. If the speed of sound is 330ms^-1 the distance between the wall is

A. 33m
B. 110m
C. 220m
D. 330m
E. 495m

Question 142:

• JAMB 1980

A cell has an open circuit voltage V₁ and a closed circuit voltage V₂ when a current is flowing through it. Therefore, the internal resistance of the cell is

A. \(\frac{V_2}{I}\)
B. \(\frac{V_1}{I}\)
C. \(\frac{(V_1 + V_2)}{I}\)
D. \(\frac{(V_1 - V_2)}{I}\)
E. \(\frac{(V_2 - V_1)}{I}\)

Question 143:

• JAMB 1980

According to Ohm's law, the ratio V/I is constant for

A. An electrolyte
B. A diode
C. A transistor
D. Silver
E. All of the above

Question 144:

• JAMB 1980

In the process of electrification by induction, the amount of induced charge in relation to the inducing charge is the

A. Same in sign and quantity
B. Same in sign but greater
C. Opposite in sign but greater
D. Opposite in sign but less
E. Opposite in sign but equal

Question 145:

• JAMB 1980

The activity of a radioactive substance depends on

A. Temperature and purity
B. Temperature and age
C. Purity and age
D. Age, purity and temperature
E. None of the above